To be fair to Harry, neither of those are good examples—Voldemort’s plan also had Hermione in Azkaban thinking she had murdered Draco Malfoy for two weeks, which would have had… unpleasant effects on her mental health, and there’s a pretty sharp limit to how much you can count “going along with a hostage situation at gunpoint” as “meddling.” A mistake, yes, intentional meddling, no.
I really don’t think the alternative was better than the canonical “Harry gets her out of there at a reasonably low cost considering all the myriad ways he has of making tons of money”.
I mean, given that his opponent turned out to be Quirrell, maybe, but otherwise...
The part that was numb with grief and guilt took this opportunity to observe, speaking of obliviousness, that after events at Hogwarts had turned serious, they really really really REALLY should have reconsidered the decision made on First Thursday, at the behest of Professor McGonagall, not to tell Dumbledore about the sense of doom that Harry got around Professor Quirrell. It was true that Harry hadn’t been sure who to trust, there was a long stretch where it had seemed plausible that Dumbledore was the bad guy and Professor Quirrell the heroic opposition, but...
Did he? The beginning of chapter 110 seems to suggest otherwise:
Dumbledore’s grimness had returned and redoubled. “There I am, searching so hard for Voldemort’s shade, never noticing that the Defense Professor of Hogwarts is a sickly, half-dead victim possessed by a spirit far more powerful than himself. I would call it senility, if so many others had not missed it as well.”
That precise wording might carry sarcastic undertones. However, the bewilderment right before that seemed (and still seems, on second reading) genuine to me:
The grimness on Albus Dumbledore’s face lasted only an instant before giving way to bewilderment. “Quirinus? What—”
And then there was a pause.
“Well,” said Albus Dumbledore. “I do feel stupid.”
There was a long pause, then. The grey eyes searched him.
“Of course...” said Lucius slowly. “I do feel the fool now. This whole time you were just pretending to have no idea what we were talking about.”
To be fair to Harry, neither of those are good examples—Voldemort’s plan also had Hermione in Azkaban thinking she had murdered Draco Malfoy for two weeks, which would have had… unpleasant effects on her mental health, and there’s a pretty sharp limit to how much you can count “going along with a hostage situation at gunpoint” as “meddling.” A mistake, yes, intentional meddling, no.
I’m not saying that the alternative was good—just that the alternative was better.
I am considering primarily the earlier mistakes Harry made with respect to Quirrell.
Was it?
I really don’t think the alternative was better than the canonical “Harry gets her out of there at a reasonably low cost considering all the myriad ways he has of making tons of money”.
I mean, given that his opponent turned out to be Quirrell, maybe, but otherwise...
Which earlier mistakes were these?
The chief of them is the one that Harry realizes:
I think Dumbledore did realize the fact that the Defense Professor is Voldemort, so that’s no consequential error on Harry’s part.
Did he? The beginning of chapter 110 seems to suggest otherwise:
That’s sarcasm.
That precise wording might carry sarcastic undertones. However, the bewilderment right before that seemed (and still seems, on second reading) genuine to me:
It’s also an eerie echo of Lucius Malfoy: